High-speed steel



Patented 2, 1940 UNITED STATES PATENT OFFICE Firth, Pit

Sterling Steel Company,

Pennsylvania No Drawing.

tsburgh, 150 88818110" to Firtha corporation of lpplioation May 24. 1939.

Serial .No. 275.486

6 Claims. (01. 75-123) J This invention relates to highspeed steel of molybdenum type. (In an application for Letters Patent, filed January 21, 1939, Serial No. 262,214, we have disclosed the discovery that boron may advantageously be included in the mix for steel of this type. It is our discovery that, boron being present in an amount that, in the twenty .examples there given. ranges from 0.10 to 0.91% of .the iron content, chromium may be entirely eliminated; and that if chromium be eliminated or (being present) is present in quantity not exceeding 1.50% of the iron content, a steel is produced that is free of anytendericy to deteriorate in heat-treatment, and a steel that posses- :es the desirable qualities characteristic of the m. Our present invention relates to the same subiect-matter and, more specifically, to the inclu- 1 sion in the mix of cobalt, either with or without "nickel also.

In accordance with this invention, an alloy may contain the following elements within the percentages given (the percentages being rela- 1 i tive to the iron content) s Carbon .80-1110 Silicon I I .05-1.00 Manganese .10-1.00 Vanadium -4 325-250 Molybdenum 5.004200 Cobalt 50-1500 Boron .05-.50

No. s1 Mn (is Vs Mo 00 Ni 11 v I .42 .10 .41100 .15 am 1.00 4.01 40 .51 .43 -.s2 .1 .40 11.00 2.02 29 .112 .111 .01 .aa .02 11.112 an 1.112 .01

.aa .aa .21 .10 .80 8.21 011 .22

.aa .aa .18 1.20 1.10 10.50 1.00 41 .14

The remainder of the compositions tabulated above will be und tood be substantially or I to iron, together with such other alloying elements and impurities as are sometimes found in this type of alloy compositions.

The above examples all containcobalt. Some contain cobalt and nickel also. Their hardening temperatures range from about 1800 F. to 2350 F. The range of drawing temperatures, at which 1200 F. The eflect of the presence of cobalt (and cobalt and nickel) is that the ranges both of hardening and of tempering temperatures (at Preferred 2"9. m sses? Pl t-2". 888888888 's 'esss's's's'e Dies which proved effective were found upon Another steel which also gave highly satisfaccomposition Efl'ective Preferred composition composition -.60-i.10 .50- 1.10 .00-1.00 .101.00 .00-1.00 .10- 1.00 .00- 1.25 .001.60 .00-250 .25-250 5.004200 15.00-12.00 JO-15.00 1. 0016.00 .00- 5.00 .00-2J50 .06- .60 .05- .60

, secondary hardness is developed is from 900 to tory results as a steel for dies and also proved superiod to 18-4-1 steel as a cutting toolferrous components, in percentages relative to the iron content, are

A tool steel alloyed in accordance with the invention which in service test was found superior to 18-4-1 and other known types of molybdenum high-speed steels was found upon analysis to contain- C Si Mn ,Cr Va Mo 00 Ni B Still better tool'steels were found to contain-- Cobalt when added to a steel in which boron is present and from which chromium is either wholly eliminated or, being present, does not exceed 1.50% of the iron content, increases redhardness, affords greater toughness, and improves the cutting quality. It, additionally, nickel also be present, higher temperature in heat-treatment is gained, and the good qualities just specified are realized in yet larger measure.

We have specified that the steel of our invention may be free of chromium; and that, if chromium be present, it should not exceed in quantity 1.50 percent of the iron content. We characterize such a steel as substantially free of chromium.

We claim as our invention:

1. A high-speed steel of molybdenum type, substantially free of chromium, whose other nonferrous components, in percentages relative to the iron content, are

together with metal of a group that consists of cobalt and nickel in quantity ranging from 0.50 to 20 percent.

2. A high-speed steel of molybdenum type, substantially free of chromium, whose other non- Percent 0 Si Mn Cr Va Mo 05 Ni 13 Cfllbfm Silicon 0.50- 1.00

.51 .42 .52 .91 .45 9.50 9.62 29 Manganese 0.10- 1.00 Vanadium; 0.25- 2.50

Molybdenum 5.00-12.00

Still better steel for dies may contain Cobalt 05045.00 Nickel Up to 5.00

0 i Mn Cr Va Mo 00 Ni B Boron x 0.05 0.50 .52 .51 .51 .93 .92 5.82 a. 51 1.52 .37 3. A high-speed steel of molybdenum type, substantially free of chromium, whose non-ferrous components, in percentages relative to the iron content, are- Percent Carbon 0.40- 0.60 SillCOIlL. 0.35- 0.80 Manganese 0.30- 0.65 Vanadi 0.25- 1.25 Molybdenum 6.00-11.00 Cobalt 1.00- 6.00 Nickel 0.25- 2.00 Boron -1 0.15- 0.40

4; A high-speed steel of molybdenum type, substantially free of chromium, whose non-ferrous components, in percentages relative to the iron content, are

. Percent Carbon 0.50- 1.10 Silicorl 0.10- 1.00 Manganese 0.10- 1.00 Vanadium 0.25- 2.50 Molybdenum, 5.00-12.00 Boron 1 0.05- 0.50

together with metal'of a group that consists of cobalt and nickel; in quantity ranging from 1.00 to 17.50 percent.

5. A high-speed steel of molybdenum type, substantially free of chromium, and of the following composition, the quantities of the non-ferrous components being given in percentage relative to the iron component: carbon, 0.62 percent; silicon,

0.57; manganese, 0.51; vanadium, 0.92; molybdenum, 5.82; cobalt, 3.51; nickel, 1.52; boron, 0.37, the residue being substantially of iron.

6. A high-speed steel of molybdenum type, substantially free of chromium, whose non-ferrous components, in percentages relative to the iron content, aretogether with metal of a group that consists of cobalt and nickel, in quantity ranging from 7.03 to 14.48 percent. 5

\ ELMER B. WELCH- LEWIS GERALD FIRTH. 

